Transcript Unit B3-1

Lesson
Understanding Animal
Digestion
Bell:
What is this?
What are the various types of
digestive systems found in animals?
 Knowledge
of the different types of
digestive systems is critical in
selecting the proper feeds for
livestock.
 Understanding the chemical and
physical changes that occur during
the digestion process leads to more
efficient livestock feeding.
Digestive Systems
 Digestion
is the process of breaking
down feed into simple substances
that can be absorbed by the body.
 Absorption
is taking the digested
parts of the feed into the
bloodstream.
Digestive Systems
 The
digestive system consists of the
parts of the body involved in
chewing and digesting feed.
– This system also moves the digested
feed through the animal’s body and
absorbs the products of digestion.
Digestive Systems
 Different
species of animals are
better able to digest certain types of
feeds better than others.
 This
difference occurs due to the
various types of digestive systems
found in animals.
Digestive Systems
 There
are four basic types of
digestive systems:
– Monogastric (simple)
– Avian
– Ruminants (polygastric)
– Pseudo-ruminants.
Monogastric
A
monogastric digestive system has
a simple stomach.
– The stomach is a muscular organ that
stores ingested feed and moves it into
the small intestine.
– The stomach secretes acid.

The acid results in a low pH of 1.5 to 2.5.
The low pH destroys most bacteria and
begins to break down the feed materials.
Monogastric
 Animals
with this type of digestive
system are better adapted to the
use of concentrated feeds, such as
grains, than the use of large
quantities of roughages.
 Examples of monogastric animals
are dogs, cats, swine and humans.
YouTube - digestive system
animation monogastric
Pseudo-ruminant
 D.
A pseudo-ruminant is an animal
that eats large amounts of roughage
but does not have a stomach with
several compartments.
– The digestive system does some of
the same functions as those of
ruminants.
– They are able to utilize large amounts
of roughages because of the greatly
enlarged cecum and large intestine.
Pseudo-ruminant
 These
animals often eat forages as
well as grains and other
concentrated feeds.
 Examples
of pseudo-ruminants are
horses, rabbits, guinea pigs, and
hamsters.
YouTube - 3D Horse Digestion Guide
What are the major parts of the
digestive system and their functions?
 The digestive system is made up of
a number of parts known as organs.
– The system beings at the mouth,
where food enters the body, and
continues until anus, where
undigested material exits the body.
– The digestive systems of most
livestock are very similar in terms of
the organs they contain.
Mouth and Esophagus
 The
chewing action of the mouth and
teeth breaks, cuts, and tears up the
feed.
 This increases the surface area of the
feed particles which aids in the chewing
and swallowing process.
 Saliva stimulates the taste of the feed
but also contains the enzymes, salivary
amylase and salivary maltase.
Mouth and Esophagus
 Enzymes
are substance called
organic catalysts that speed up the
digestive process.
 Salivary amylase changes starch to
maltose or malt sugar.
 Salivary maltase changes maltose
to glucose.
Small Intestine
 1.
Pancreatic juice secreted by the
pancreas, contains the enzymes
trypsin, pancreatic amylase,
pancreatic lipase, and maltase.
 Trypsin breaks down proteins not
broken down by pepsin.
 Some of the proteoses and
peptones are broken down by
trypsin to peptides.
Pancreatic Juice
 Proteoses,
peptones, and peptides
are combinations of amino acids.
– Proteoses are the most complex
compounds and peptides are the
simplest.
 Lipase
works on fats in the feed.
– It changes them into fatty acids and
glycerol.
Pancreatic Juice
 Pancreatic
amylase changes starch
in the feed to maltose.
 Sugar and maltose are then broken
down even further by maltase.
 They are then changed into a simple
sugar called glucose.
Bile
 Bile
is a yellowish-green, alkaline,
bitter liquid produced in the liver.
– Bile is stored in the gall bladder in all
animals except horses.
– Bile aids in the digestion of fats and
fatty acids.
– It also aids in the action of the enzyme
lipase.
Intestinal Juice
 Glands
in the walls of the small intestine
produce intestinal juice.
– This fluid contains peptidase, sucrase,
maltase, and lactase, all enzymes used in
digestion.
– Proteoses and peptones are broken down
by peptidase into amino acids.
– Starches and sugars are broken down by
sucrase, maltase, and lactase into the
simple sugars, glucose, fructose, and
galactose.
Large Intestine
 The
main function of this organ is to
absorb water.
 Material
not digested and absorbed
in the small intestine passes into the
large intestine.
Large Intestine
 Feed
materials that are not digested
or absorbed are called feces.
 This material is moved through the
large intestine by muscles in the
intestinal walls.
 The undigested part of feed is
passed out the body through the
anus, the opening at the end of the
large intestine.
Review / Summary
 What
are the various types of
digestive systems found in animals?
 What are the major parts of the
digestive system and their
functions?